Auroras are lightshows that typically occur at high latitudes such as the Arctic and Antarctic; however, they expand equatorward under severe magnetic storms. Past observations of such unusual auroras can therefore allow us to determine the frequency and severity of magnetic storms. The more information that can be gathered about historic intense magnetic storms, the greater the opportunity to mitigate disruption of power grids in a future event.
Auroras are lightshows that typically occur at high latitudes such as the Arctic and Antarctic; however, they expand equatorward under severe magnetic storms. Past observations of such unusual auroras can therefore allow us to determine the frequency and severity of magnetic storms. The more information that can be gathered about historic intense magnetic storms, the greater the opportunity to mitigate disruption of power grids in a future event.
Historical documents are becoming much more accessible for research as newly discovered records surface from private collections across the world. Researchers centered at Tokyo’s National Institute of Japanese Literature (NIJL) and National Institute for Polar Research (NIPR) examined a detailed painting from a Japanese manuscript Seikai (“understanding comets”) with associated commentary describes a red aurora occurring over Kyoto on 17 September 1770. Also investigated were detailed descriptions of the event from a newly discovered diary of the Higashi-Hakura family of Kyoto.
“The enthusiasm and dedication of amateur astronomers in the past provides us an exciting opportunity,” Kiyomi Iwahashi of NIJL says. “The diary was written by a kokugakusha (scholar of ancient Japanese culture), and provides a sophisticated description of the red aurora, including a description of the position of the aurora relative to the Milky Way.”
Read more at National Institute of Polar Research
Image: The painting of the red aurora of Sept. 17 1770 in the premodern Japanese text "Seikai," which is owned by the Matsusaka City Museum of History and Traditional Crafts. A radial structure of stripes is shown, comprising small-scale rays inside the stripes. The bottom section and eastern/western edges of the stripes are somewhat darkened. The caption on the right-hand side may be translated as follows, "On 17 September 1770, at night, red vapor was active at northern sky. The figure was as it watched at midnight." (Credit: Matsusaka City, Mie Prefecture)
